Using a dynamic microsimulation model, a research team, including APARC Deputy Director and Asia Health Policy Program Director Karen Eggleston, shows that there are differentially positive health gains of smoking reduction among subgroups of smokers in South Korea, Singapore, and the United States.

Tobacco use is responsible for the death of approximately eight million people worldwide, estimates the World Health Organization, and countries are increasingly making tobacco control a priority. Indeed the relationship between smoking and the burden of chronic diseases such as cancer, lung disease, and heart disease, and, in turn, premature mortality, is well documented. Yet little is known about the health effects of smoking interventions among subgroups of smokers.

Do interventions targeted at heavy smokers relative to light smokers lead to disproportionately larger improvements in life expectancy and prevalence of chronic diseases? And how do these effects vary across populations? In today’s rapidly aging world, it is crucial to understand the potential health gains resulting from interventions to reduce smoking, a leading preventable risk factor for healthy aging.

That’s why a research team, including APARC Deputy Director and Asia Health Policy Program Director Karen Eggleston as well as Stanford Health Policy faculty member Jay Bhattacharya, set out to examine the health effects of smoking reduction. To do so, the team simulated an elimination of smoking among subgroups of smokers in South Korea, Singapore, and the United States.

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The team’s findings, discussed in a new paper published by the journal Health Economics, show that smoking reduction can achieve significant improvements in lifetime health as measured by survival while also reducing the prevalence of major chronic diseases, though the effects are heterogeneous. Whereas interventions in both subgroups and in all three countries led to an increased life expectancy and decreased prevalence of chronic diseases, the life-extension benefits were greatest – 2.5 to 3.7 years – for those who would otherwise have been heavy smokers, compared with gains of 0.2 to 1.5 years among light smokers.

The team developed a dynamic microsimulation model to estimate the health gains of reducing smoking among heavy smokers and light smokers. Microsimulation models are powerful tools for assessing the value of health promotion: they model individual health trajectories while accounting for competing risks, thus providing valuable information about the impact of interventions and how they may interact with the changing demographics and socioeconomic profile of a population to determine future health. The team’s study applied microsimulation models tailored to the demographic and epidemiological context in the three countries, then compared the gains in survival and reduction in chronic disease prevalence from a given reduction in smoking and how these impacts vary depending on initial smoking intensity.

The team’s findings indicate that there are differentially positive health effects from smoking reduction. The life‐year gain among heavy smokers quitting well exceeds that of light smokers quitting in each country, but the magnitudes differ substantially: 11.2 times for South Korea, 6.8 times for Singapore, and 1.7 times for the United States. The lower life expectancy among Americans is related to the greater extent in which they suffer from risk factors, such as obesity, relative to the Asian counterparts in the study.

The findings illustrate how smoking interventions may have significant economic and social benefits, especially for life extension, that vary across countries. They are particularly important for aging societies that are concerned about the sustainability of their health insurance systems in the face of increasing burden of chronic disease.